الفهرس 
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Abstract
A total of 100 random samples of some edible beef offal represented by liver, heart, lung and spleen (25 of each) were subjected to bacteriological examination for Mesophilic count, Enterobacteriaceae count, Coliforms count, Staphylococcal count, the incidences of S. aureus, E. coli, Salmonellae and serotyping of E. coli and Salmonella and detection of enterotoxin genes of S. aureus and Shiga toxin (stx1 & stx2) genes of E. coli to evaluate their quality.
The mean values of Mesophilic count / g of liver, heart, lung and spleen were 3.9×104, 3.6×104, 3.03×104 and 5.4×104 cfu/g, respectively.
The mean values of Enterobacteriaceae count / g of liver, heart, lung and spleen were 2.3×104, 1.4×104, 1.2×104 and 1.5×104 cfu/g, respectively.
The mean values of Coliforms count / g of liver, heart, lung and spleen were 6.4×102, 5.6×102, 6.1×102 and 8.2×102 MPN/g, respectively.
The mean values of Staphylococcal count / g of liver, heart, lung and spleen were 1.1×102, 1.1×102, 1.3×102 and 1.7×102 cfu/g, respectively.
The incidence of S. aureus isolated from examined liver, heart, lung and spleen samples were 36%, 44%, 64% and 32%, respectively.
The incidence of Escherichia coli isolated out of 25 examined liver samples were 60% {2(13.33%) EPEC, 6(40%) EHEC, 5(33.34%) ETEC and 2(13.33%) EIEC}. While in heart were 28% out of 25 examined samples {4(57.14%) EPEC, 2(28.57%) EHEC and 1(14.29%) ETEC}. In lung were 44% out of 25 examined samples {4(36.36%) EPEC, 4(36.36%) EHEC and 3(27.28%) ETEC}. In spleen were 48% out of 25 examined samples {4(33.33%) EPEC, 4(33.33%) EHEC, 2(16.67%) ETEC and 2(16.67%) EIEC}.
Isolated E. coli were serotyped into O124, O125:H21, O127:H6, O128:H2, O26:H11, O111:H4, O119:H4 and O55:H7 serovers from liver samples and O125:H21, O111:H2, O119:H4, O55:H7 and O86 serovers from heart samples, while O127:H6, O128:H2, O26:H11, O111:H2, O119:H4 and O55:H7 serovers from lung samples and O124, O128:H2, O26:H11, O111:H2, O114:H21, O142 and O44:H18 serovers from spleen samples.
The incidence of Salmonellae isolated out of 25 examined liver samples were 4(16%) {2(50%) S. Typhimurium group B var O: 1, 4, 5, 12 , H: i: (1,2) and 2(50%) S. Enteritidis group D1 var O: 1, 9, 12 , H g, m : - }. While in heart were 5(20%) out of 25 examined samples {2(40%) S. Typhimurium group B var O:1,4,5,12 , H: i: (1,2) , 1(20%) S. Enteritidis group D1 var O: 1, 9, 12 , H g, m : - , 1(20%) S. Anatum group E1 var O: 3, 10, 15, 34 , H: e, h: (1,6) and 1(20%) S. Infantis group C1 var O: 6, 7 , H: r: (1,5)}. The lung recorded 8(32%) out of 25 examined samples {2(25%) S. Typhimurium group B var O: 1, 4, 5, 12 , H: i: (1,2) , 4(50%) S. Enteritidis group D1 var O: 1, 9, 12 , H g, m : - , 1(12.5%) S. Virchow group C2 var O: 6, 7, 14 , H: r: (1,2) and 1(12.5%) S. Anatum group E1 var O: 3, 10, 15, 34 , H: e, h: (1,6)}. The spleen recorded 7(28%) out of 25 examined samples {2(28.6%) S. Typhimurium group B var O: 1, 4, 5, 12 , H: i: (1,2) , 3(42.8%) S. Enteritidis group D1 var O: 1, 9, 12 , H g, m : - , 1(14.3%) S. Virchow group C2 var O: 6, 7, 14 , H: r: (1,2) and 1(14.3%) S. Heidlberg group B var O: 1, 4, 5, 12 , H: r: (1,2)}.
Analysis of the PCR products obtained from amplification reaction of extracted DNA from 10 identified S. aureus strains in this study for detection of enterotoxins genes by agarose gel electrophoresis revealed that the specific band for sea gene (120bp) was detected in 3(30%) one from liver, heart and spleen out of 10 isolates, while the specific band for seb gene (478bp) was not detected in any isolate. The specific band for sec gene (257bp) was detected in 1(10%) from lung out of 10 isolates, also the specific band for sed gene (317bp) was detected in 1(10%) from lung out of 10 isolates. The specific band for sea, sec genes (120bp, 257bp) was detected in 1(10%) from spleen out of 10 isolates.
Analysis of the PCR products obtained from amplification reaction of extracted DNA from 12 identified E. coli strains in this study for detection of Shiga toxins (stx1 & stx2) genes by agarose gel electrophoresis revealed that the specific band for stx1 gene (614bp) was detected in 3(25%) for strains O86, O127:H6, O114:H21 out of 12 isolates, also the specific band for stx2 gene (779bp) was detected in 3(25%) for strains O119:H4, O44:H18, O142 out of 12 isolates. While the specific band for both stx1 and stx2 genes (614bp, 779bp) was detected in 5(41.7%) for strains O111:H4, O55:H7, O125:H21, O26:H11, O128:H2 out of 12 isolates. The occurrence of these genes sequences that code for toxin production increase the virulence and the public health hazard of this bacteria.
The public health significance of isolated microorganisms and possible sources of contamination of edible beef offal with these organisms as well as suggestive hygienic measures to improve the quality of offal were discussed and control measures were taken from the moment of animal slaughtering until consumption to reduce contamination of these offal.